Telephone-receiver unit



ffand4 State of Michigan,

Parenteel-m2, 1926.

-UMNITED ,sTar-ieis jPfATEN-rOFFICE,

vnUGHN n. MORRISON, or nIiTRoIrM'IcHIGnN, assIerivoR',y BY'DIRECT AND' MESN ASSIGNMENTS, `0F MIoHIGaN.

Application filed February 3,I 1923. Serial 17o. 616,681.

VTo all 'whom t may' concern:

Be it known that I, VAUGHN E. MORRISON,

a citizenof the United vStates ofAmerica,

.residing at Detroit, in the county of vWayne have invented certain new and useful Improvements in Telephone-Receiver Units, of which the following is a specification, reference being had therein to the accompanying drawings.

Thisinvention relates to instruments for making audible, electrically transmitted messages,vand more particularly to those instruments known as telephone receivers and which embody a diaphragm or the like operatedby an electro-magnetunder the influence ofcurrent variations.

' v- It is. a well known principle offoperation A of. a magnet thatl its eld'strength Lor at- `ractive, pull upon its armature ,Varies in yersely as the square ofthe distance between itsjpole and armature, and in telephone re ceivers as commonly constructed, `this distance between terminal or magnet poleand armature or kdiaphragm is fixed inthe construction of the phone, that is,l magnetand diaphragm are not l relatively adjustable to vary the Jair gap. y "L The object of the present-invention is to provide an adjustment wherebyfthje'normal distance or air gap between magnet pole and diaphragm o r other armature may be varied to vary the influence-,of the magnet upon Athe diaphragm for the'purpose-of securing best results in use of the Aphone under the influence of electrical currents having different energizing effects upon the electroinagnet.

A further object is to provide a simple and efficient construction having certain other new and useful features, all as herein` after more fully described. I

lVi'th the above and other ends in view,

. fthe invention consists in the several matters hereinafter set forth and more particularly vpointed `out m ,the appended claims, referi vence being had to the -accompanying draw ings in which k- Fig. 1 is a plan view of a common form of telephone receiver with 'its cap or cover removed; A

Fig. Qris a transverse section of the receiver shown in Fig, l, with its cap in place and embodying adjusting means, the con lro IMoRmson LABoRAToRIns, INCORPORATED, A coRroRAiIoN .TELEPHONE-RECEIVER unir. i

struction being illustrative of an embodif `ment of the present invention;

showing amodifled construction particularly adapted for luse in A.conjunction with an amplifying horn or the-like;

`Figa 4 is a transverse section through the casing ofa receiver showing interior mechavmovements 'off the diaphragm to reproducel the soundl ofthe vtransmitted message.

When' the `transmission of messages is effected radio or other means operating with comparatively small current, -it is par-` ticularly advantageous to .have a verysens- 4tivereceiver so that thediaphragm will be operated by the smallest current impulses passing through themagnetic coil to accuratelyl reproduce all of the Atransmitted sounds; and as the magnetic pull exerted on the diaphragmis proportioned to the square of the magnetic ieldstrength,` and as the pull exerted on the magnet armature lvaries inversely as the-square of the distance bef l tween the arma-ture and the pole of the mag-- net, by varying this distance or air gap the influence of :the magnet upon the arma` ture or diaphragm is varied.l Therefore if it is found that the received current is smalleil than the receiver was designed to be efficiently operated by, a very slightadjustment of the'magnet and armature ltoward each other, will give 'an increase of magu netic pull upon the armature suicientto'VV make the-receiver efficiently operati-ve with the reduced current. Likewise an increase in the air gap willina-ke the receiverl oper.- f

- ate eiiicientlywith larger current than itw'a's designed to be mostleiiicientlyoperated by. lIn radio broadcasting-,thestrength of the received current impulsesdepends primarily sirable to provide means for varying the. sensitiveness of the receiver 1n order to meetl 'piece 5 is screw-threaded upon the casing to upon the sending apparatus and the distance from the sending station at which the transmitted 'message is received and as the radio energyA output varies from time to time and as atmospheric and other conditions may` vary the strength of the received current impulses, itis obvious that it is highly dethese slight variations in strength of current impulses received.

1n the drawings, the simplest and most common construction of receiver is shown as an illustration of an application of the in-y vention, and variations of this simple construction are shown to illustrate various ways of constructing this type of receiver to eifect an adjustment of magnet and armature relatively. Therconstruction shown-in Fig. 1 and 2 comprisesthe usual casing 1 within which is mounted a plurality of superposed permanent magnets, or a'magnet formed of a plurality of permanently mag-I netized metal strips secured together to form a magnet 2 of the horse-shoe type, with polie 'pieces Supon 'which are wound coils 4 connected in series in the incoming 'or message transmitting circuit. The usual cap or ear close the open side thereof and a exible diaphragm 6 or metal disk is positioned Within said cap with peripheral portion clamped between tlie'edgeV of the annular wall of the casing, -and the cap to holdA said disk positioned adjacent to and spacedslightly from the pole pieces of the'magnets and to bc flexed by the attractive force of the permanent magnet and by theinuence thereon of current passing through the coils 4, to re roduce (in the usual manner) the sounds o the transmitted message and make the message i audible through the central opening 7 inthe cap or ear piece 5.

To provide for'an adjustment of the diaphragm which-forms an armature for thev magnet, and the pole pieces l3, relatively, to vary the air gap andv thus vary the pull of the magnet upon the dia phragm, rin annular strips 8, of yieldab e, compressi le or resilient'material are interposed, one' he-` tween' the peripheral portion of the diaphragm, and. theedge of the casing wall and' the other between the diaphragm and the cap` so that by screwing the cap upon the casing,

these rings will ,be compressed andthe dia-` phragm thus adjusted toward. Athe pole i pieces.l By a rotation of the cap uponthe casing, a very accurate and minute adjustment of the diaphragm may thus be secured by verysimplemeans applicable to receivers as commonlyl constructed.

In Fig. 3, aconstruction of receiver is shown which will providea very fine and accurate adjustment ofl diaphragm, and which is such as to make the receiver particularly adaptable 'foruse with anamplifying horn.

to slide within a shell comprising an annular ring or wall..9 provided with, a closure plate 10 at one end havingcentral openings 11 tov permit the sound waves to escape and is L closed at its opposite end by a screw-threaded closure 12 having a central aperture in which is mounted astud or boss 13 having. an axial screw-threaded bore to receive an adjustingend and adapted to bear at its i against the end wall ofthe Casin,D axis thereof. A lock nut 15 is also provided screw 14 having a knurled head atryis outer on said screw to engage the closure and lock the screw in any position to which it may be adjusted. VAAhorn carrying cap 16 is in screw-threaded.engagement with the end of the shell having the closure plateor disk 1'0, and'this'cap has a central opening within which the endY of a suitable amplifying horn 16 'm ay be secured.`

The diaphragm 6 is` clamped.l at its periphery between. the end edge of the annular casm In this constructiom'the casing 1 is fittedv er. end 1 at the walland the plate 10 with the compressible rings 8 interposed, and thus by turning the adjustino'v screw `14 the casing 1 may be adjusted wit-Rin the Shen ringe to:

Ward the plate 10 and thus compress said rings 8 to agreater or lesser extent and moving the diaphragm and magnet pole pieces relatively.

A similar relative adustment of diaphragm and pole pieces may be secured by means of the construction shown in Fig.l 4 Where-.

in the casing l1 is inclosed within an outer shell as in. Fig. 3 and adjustment of the cas' ing is Asecuredthrough Athe provision of an adjusting cap 17 having an annular flange in screw-threaded engagement with lexternal screw threads on the shell, 'and a ring 18 is interposed between said cap 17 and the bot.

tom of thecasing 1 to force the casing to move toward the diaphragm when the ad;-

justing cap is turned and thus adjust the pole pieces and diaphragm relatively.

A construction` very similar to that shown in Fig.- 4, is shown in Fig. 5, the only dif- -ferenceb'eing in the substitution of a central 'stud 19'0'11 Athe adjusting cap 17 for the ringV 18', said stud engaging the bottom wall of thc casing 1 atthe axis thereof to move the casinfr the "screw, and, as the magnet iscarriedby said Wall,l said magnet Will-be moved toward the diaphragm which is clamped sodidly at its periphery between the end edge "of theannular Wall of the casing-and the endfwall of the shell.

In the several figures are therefore-illus-- adjustment may also be attained in connec-` ftion With other types and construct-ions of telephone receivers, the relativeadjustment of magnet or magnets and member or members attracted or repelled thereby to repro duce sound throu ,h diaphragm vibration, being contemplated. l

Having thus fully described my invention,

l. A ,device of the' character described comprising a casinghavingan open side, a shell Within which thecasing is slidable, an

electro-magnet" mounted Within the ,casing andv provided vWith pole pieces directedto- Ward the `open side ofQthe casing, a dia- Aphragm supported across the open side ofthe casing .andfadjacent the pole pieces and free'from engagement with the shell, van apertured cover plate secured to the shell and; arranged to` limit movement of the dia- 'phragm in one direction, resilient means 46 magnet mounted in the casing and having pole pieces projecting toward the open l'side ot-the casing, a. shell enclosing the casing andjwithin which the casing is slidable, a diaphragm mounted across the open side of the casing-iand freeV from engagement `With the shell, an apertured cover'pl-ate secured on the shell and arrangedto limit` movement of the diaphragm in one direction, 'aresilient ring member interposed between the annular edgeportion of the diaphragmnand the anf nular en'd face of the Wall of'the casing, and adjusting means vvcarried by the shell for moving` the casing Within theshell to com pressgthe resilient ring and so adjust the diaphragm andjpole pieces relatively'.

3. A device of the lcharacter. described comprisinga casing having a bottom Wall andan annular sidewall, shell enclosing the casing and Within which' the casing is sldabl'e, a diaphragmk across the open side of the casinggan electro-magnet mounted in the casing and havingpole pieces directed toward the diaphragm, and free from enj'gagement with theshell, an aperturedcover plate secured to the; shell. and arranged to limt'movement of the diaphragm -in one direction, resilient means arranged between the diaphragm and cas1ng,vand an adjusting screw carried by the shell and engaging the bottom Wall of the casing at the axis of the reusing -for adjusting said casing Within the shell to adjust the diaphragm 'and pole pieces relatively.

4. In a Vdevice o'f the character the combination of an inner cup-shaped casing, an outershell enclosing the casing and Within which the casing is slidable, an electro-magnet mounted Within tlhe casing upon itheibottom"wall thereof and having pole pieces directed toward the open end of the casing, a diaphragm Within the shell eXtenddescribed,

ing across the open side-of the casing, a reysilient rubber ringinterposed between the shell a'nd the edge portion of the diaphragm, an apertured cover plate'secured on the shell, a second rubber ring interposed between the ,annular 'edge' portion of the diaphragm and theV cover plate, said rubberA rings being 'formed with flat side surfaces to engage and `lie. Hat upon the sides 'of the diaphragm ythroughout the entire edge portion thereof, and an adjusting member carried by the shell 'and engaging the casing to slide the casing Withinthe 'shell and compress the rubber rings to clamp the diaphragm and to adjustsaid diaphragm and pole pieces relatively. l

5. A. device of the character described comprising van inner cup-shaped casing having an annular side Wall'and a bottom Wall, an electro-magnet' secured Within the casing upon the 'bottom Wall thereof` and having pole pieces directed toward the open end of the casing, a shell enclosing the casing and Within Which the casing is slidable1 all dia- 'phragm extending across the open. side of the casing and fre-e from engagement with the shell, and a thumb screw extending through Atheend Wall ofthe shell and engaging the bottom Wall of the casing for adjustingfthe casing Within the shell.. l 4

`6. .A device of the,` character described comprising a cup-shaped shell having an Openside, a casing having an annular side AWall slidably titte-d Within-the shell, an electromagnet secured Within thecasing and having pole-pieces directed toward the open Asid'e of the shell, a-rubber ring restingv upon the edge of the annular Wall of thecasing, a

Adiaphragm resting upon said rubber ring, a4

,secondv rubber jring rest-ing uponl the dia-l phragm, an apertured cover plate secured over the openside of the shell andV adapted to compress' the rubber rin-gs and -so adjust the diaphragm and pole-pieesrelativelv. 7. A- device of the'character described comprising. a cup-shaped shell havingcanA open side, a casing having an annular side wall slid'flblf,7 ated within the shell, un electro-nmgnety secured Within the casing;d and having pole-pieces directed toward the open side of the shell', a flatresilient ring resting upon the upper ed e of the annular Wall of the casing, a, dia

the first resilient ring, an -apert11red coverV ragm arranged With` its outer portion restlng .upon said resilient' Liv/1,454

platte detachably secured on the shell vand adapted to engage the uppermost resilient rm A Slielgl :11nd engagin the casing to slide the easing within the s ell-and compress the resilient rings to clamp the diaphragm therebetween -and'to adjust the diaphragm and pole-pieees relatively.

In testimony whereof I aflix my signature.

' VAUGHN MORRISON.

and a rotatable member carried by the 

